Self-supporting casing string for horizontal section of horizontal well

Abstract

The invention relates to the technical field of horizontal well horizontal section fixing equipment, in particular to a self-supporting casing pipe string for a horizontal well horizontal section, and aims to solve the problems that in the related technology, when cement is adopted for well cementation, a casing pipe adheres to the wall, wide and narrow ring space displacement is uneven, and consequently the thickness of a cement ring is uneven and even local loss is caused. And the well cementation effect is not good. The self-supporting casing string for the horizontal section of the horizontal well is provided with a plurality of sections of self-supporting casings which sequentially enter the well through a feeding tool, butt joint is achieved through the connector assemblies and the connector assemblies at the two ends of the casing bodies, meanwhile, the anchoring assemblies in the connector assemblies are triggered, the respective supporting casings complete supporting and anchoring, and therefore pipe column anchoring is achieved. The technical problem that in an existing horizontal well cementation scheme, when cement is adopted for well cementation, a casing adheres to the wall, space displacement of a wide ring and a narrow ring is uneven, the thickness of a cement ring is uneven, even local loss is caused, and then the well cementation effect is poor is solved.

Description

Technical Field

[0001] This invention relates to the field of horizontal well horizontal section fixing equipment, and more particularly to a self-supporting casing string for horizontal well horizontal sections. Background Technology

[0002] Cementing requires establishing a cemented barrier between the wellbore and casing to achieve formation isolation and tubing anchoring. Current practices typically employ cement cementing, where gravity drives the casing to the target depth, followed by pumping in cement slurry to completely fill the annulus. However, with well inclinations approaching 90 degrees, gravity causes the casing to adhere to the lower wall, resulting in a wide and narrow crescent-shaped annulus with higher flow velocities on the wider side and lower velocities on the narrower side. Drilling fluid retention leads to uneven cemented zone thickness and even localized gaps. In recent years, staged injection has been adopted to improve displacement, but this results in a narrower down-the-hole speed window, an increased number of waiting-to-cure stages, longer operation time, and a higher risk of casing deformation under repeated pressure and torsion, making it difficult to guarantee cementing quality.

[0003] Existing horizontal well cementing solutions suffer from technical problems such as uneven casing adhesion to the wall and uneven displacement of the wide and narrow annulus spaces during cement cementing, leading to uneven cement annulus thickness or even localized missing sections, which in turn results in poor cementing performance. Summary of the Invention

[0004] The purpose of this invention is to provide a self-supporting casing string for the horizontal section of a horizontal well, in order to solve the technical problem in related technologies where, due to the casing adhering to the wall during cement cementing, uneven displacement of the wide and narrow annulus spaces leads to uneven thickness of the cement annulus or even local missing parts, resulting in poor cementing effect.

[0005] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows: The self-supporting casing string for the horizontal section of a horizontal well provided by this invention includes: Multiple self-supporting casings are connected end-to-end. Each self-supporting casing includes a casing body, an interface assembly, a connector assembly, and an anchoring assembly. The interface assembly and the connector assembly are located at opposite ends of the casing body. Adjacent self-supporting casings are connected via insertion of the connector assembly into the interface assembly. Simultaneously, the anchoring assembly installed within the interface assembly is triggered to radially expand, thereby anchoring the self-supporting casing to the wellbore.

[0006] Specifically, the interface component includes an interface segment, which is fixedly disposed at one end of the pipe body and has multiple radial grooves formed around its own axis. The anchoring component includes multiple anchors, with each radial groove having a sliding anchor, and the radial extension of the anchor is used to anchor the pipe body to the well wall.

[0007] Specifically, the anchoring assembly further includes a stop, and the radial groove sidewall has a small hole. The anchor has a slot, and the stop is inserted into the small hole and engaged in the slot of the anchor to limit the anchor's movement, thereby preventing the anchor from extending before reaching the target position. When the self-supporting sleeve reaches the target position and the connector assembly is inserted into the interface assembly, the stop is sheared and broken, thereby releasing the anchor.

[0008] Specifically, the anchor has a cutting edge at one end near the well wall. The joint assembly has a tapered positioning section, which, through contact with the anchor, causes the anchor to extend outward along the radial groove and drives the cutting edge to insert into the well wall, thus achieving anchoring.

[0009] Specifically, the anchor is further provided with a force-applying seat at the end away from the cutting edge, and the force-applying seat has an arc-shaped structure. Multiple force-applying seats form a gap ring, and the gap ring expands radially through the contact between the force-applying seat and the conical positioning section, thereby driving the anchor to extend outward along the radial groove and driving the cutting edge to insert into the well wall, thus achieving anchoring.

[0010] Specifically, the radial groove near the interface component is further provided with a receiving groove, the receiving groove having the same shape as the side of the force-applying seat away from the interface component, for accommodating the force-applying seat when the anchor expands radially.

[0011] Specifically, the connector assembly further includes a compression anchoring section and a transition section. Along the insertion direction of the tapered positioning section, the tapered positioning section, the transition section, and the compression anchoring section are connected sequentially. The transition section is a cylindrical tube structure with a diameter smaller than the tube body, used to ensure that the connector assembly and the interface assembly have sufficient insertion depth to achieve stable docking. The compression anchoring section is tapered, used to achieve a wedge-tight docking with the interface section. The axial insertion of the connector assembly sequentially passes through the tapered positioning section, the transition section, and the compression anchoring section to complete the guiding, docking, and wedge-tightening operations.

[0012] Specifically, a breakable annular groove is provided between the transition section and the conical positioning section. When the pumped fluid injected from the ground impacts the conical positioning section, the breakable annular groove breaks, causing the conical positioning section to separate from the transition section, thereby removing the conical positioning section's restriction on the pipe diameter.

[0013] Specifically, the inner wall of the conical positioning section is also provided with crack-prone grooves, and multiple crack-prone grooves are evenly distributed around the axis of the conical positioning section. When the pumped fluid injected from the ground impacts the conical positioning section, each of the crack-prone grooves breaks, causing the conical positioning section to disperse into multiple fragments smaller than the pipe diameter, which can then detach from the self-supporting sleeve along with the pumped fluid.

[0014] Specifically, both the easily broken ring groove and the easily cracked groove are provided with multiple easily broken holes.

[0015] Based on the above technical solutions, the beneficial effects of the present invention are analyzed as follows: This invention provides a self-supporting casing string for the horizontal section of a horizontal well, comprising: Multiple self-supporting casings are connected end-to-end. Each self-supporting casing includes a casing body, an interface assembly, a connector assembly, and an anchoring assembly. The interface assembly and the connector assembly are located at opposite ends of the casing body. Adjacent self-supporting casings are connected via insertion of the connector assembly into the interface assembly. Simultaneously, the anchoring assembly installed within the interface assembly is triggered to radially expand, thereby anchoring the self-supporting casing to the wellbore.

[0016] In practical application, one section of the self-supporting casing is installed at the front end of the insertion tool and inserted into the well using the insertion tool. The connector assembly is the lower end, and the interface assembly is the upper end. After the first section of the self-supporting casing reaches the bottom, it stops moving. The insertion tool is then separated from the current self-supporting casing and pulled out, and the next section of the self-supporting casing is inserted. The connector assembly of the subsequent self-supporting casing is inserted into the interface assembly of the previous self-supporting casing to achieve docking. Simultaneously, the anchoring assembly installed on the interface assembly is triggered by the insertion action of the connector assembly, and the current self-supporting casing is anchored to the wellbore through radial expansion. The insertion tool is then separated from the current self-supporting casing and pulled out, and the next section of the self-supporting casing is inserted, repeating this process multiple times. Multiple sections of the self-supporting casing are sequentially docked to form a complete casing string, with each section of the self-supporting casing anchored to the wellbore, meaning the entire casing string is anchored to the wellbore.

[0017] As can be seen, compared with existing technologies, this self-supporting casing string for horizontal well sections is equipped with multiple sections of self-supporting casing that are sequentially inserted into the well using a drive tool. The casing is connected via connector assemblies and interface assemblies at both ends, simultaneously triggering the anchoring assembly within the interface assembly. Each self-supporting casing then completes its support and anchoring, thereby achieving string anchoring. This overcomes the technical problems of existing horizontal well cementing schemes where uneven displacement of the wide and narrow annulus spaces during cementing leads to uneven cement annulus thickness or even localized gaps, resulting in poor cementing performance. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 A schematic diagram of the combined structure of a self-supporting casing string for a horizontal section of a horizontal well, provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure before the two self-supporting sleeves are combined. Figure 3 This is a schematic diagram of the structure after two self-supporting sleeves are combined. Figure 4 A cross-sectional schematic diagram showing the contact between the anchoring component and the tapered positioning section; Figure 5 This is a cross-sectional schematic diagram of the connection between the stop and the anchor. Figure 6 This is a schematic diagram of the connector assembly.

[0020] icon: 100. Pipe body; 200, Interface component; 210, Interface segment; 201, Radial slot; 202, Receiving slot; 300. Joint assembly; 310. Conical positioning section; 320. Extrusion anchoring section; 330. Transition section; 301. Fragile ring groove; 302. Crackable groove; 400, Anchoring component; 410, Anchor; 401, Slot; 411, Cutting edge; 412, Force-applying seat; 420, Stop. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0024] Existing horizontal well cementing solutions suffer from technical problems such as uneven casing adhesion to the wall and uneven displacement of the wide and narrow annulus spaces during cement cementing, leading to uneven cement annulus thickness or even localized missing sections, which in turn results in poor cementing performance.

[0025] In view of this, the present invention provides a self-supporting casing string for the horizontal section of a horizontal well, comprising: Multiple self-supporting casings are connected end-to-end. Each self-supporting casing includes a casing body 100, an interface assembly 200, a connector assembly 300, and an anchoring assembly 400. The interface assembly 200 and the connector assembly 300 are located at opposite ends of the casing body 100. Adjacent self-supporting casings are connected by inserting the connector assembly 300 into the interface assembly 200. Simultaneously, the anchoring assembly 400, installed within the interface assembly 200, is triggered to expand radially to anchor the self-supporting casing to the wellbore.

[0026] In summary, the self-supporting casing string for the horizontal section of a horizontal well provided by this invention can achieve the following technical effects: This self-supporting casing string for horizontal well sections consists of multiple self-supporting casing sections that are sequentially inserted into the well using a drive tool. The casing is connected via connector assemblies 300 and interface assemblies 200 at both ends of the casing body 100. Simultaneously, the anchoring assembly 400 within the interface assembly 200 is triggered, allowing each supporting casing section to complete its anchoring and thus achieving casing string anchoring. This overcomes the technical problems of existing horizontal well cementing schemes where uneven displacement of the wide and narrow annulus spaces during cementing leads to uneven cement annulus thickness or even localized gaps, resulting in poor cementing performance.

[0027] The following combination Figures 1 to 6 The structure and shape of the self-supporting casing string for the horizontal section of a horizontal well provided in this embodiment are described in detail below: Regarding how the anchoring assembly 400 anchors the self-supporting casing to the wellbore, specifically: The interface assembly 200 includes an interface section 210, which is fixedly disposed at one end of the pipe body 100 and has multiple radial grooves 201 formed around its own axis. The anchoring assembly 400 includes multiple anchors 410, with each radial groove 201 having a sliding anchor 410. The radial extension of the anchor 410 is used to anchor the pipe body 100 to the well wall. The interface section 210 is threadedly connected to the delivery tool. After the self-supporting casing is anchored, the relative rotation between the delivery tool and the current self-supporting casing causes disengagement, thereby separating the delivery tool from the current self-supporting casing. The delivery tool can optionally be a booster, a hydraulic sliding sleeve pusher, or a gravity sliding sleeve guide tool, etc.

[0028] Regarding how the self-supporting sleeve avoids incorrect anchoring position due to premature extension of anchor 410, specifically: The anchoring assembly 400 also includes a stop 420, and a small hole is formed in the side wall of the radial groove 201. The anchor 410 has a slot 401, and the stop 420 is inserted into the small hole and engaged in the slot 401 of the anchor 410 to limit the anchor 410, thereby preventing the anchor 410 from extending before reaching the target position. When the self-supporting sleeve reaches the target position and the connector assembly 300 is inserted into the interface assembly 200, the stop 420 is sheared off, thereby releasing the anchor 410. The stop 420 is a shear pin, which restricts the radial extension of the anchor 410 by abutting against the slot 401.

[0029] To maximize the insertion depth of the anchor 410 and enhance the connection stability between the anchor 410 and the well wall after extension, in this embodiment, the anchor 410 is provided with a cutting edge 411 at the end near the well wall. The joint assembly 300 is provided with a tapered positioning section 310, which is used to drive the anchor 410 to extend outward along the radial groove 201 by abutting against the anchor 410, and to drive the cutting edge 411 to insert into the well wall to achieve anchoring.

[0030] To increase the effective contact area between the joint assembly 300 and the anchor 410 and enhance the force transmission effect of the insertion action of the joint assembly 300 on the anchor 410, a force-applying seat 412 is provided at the end of the anchor 410 away from the cutting edge 411. The force-applying seat 412 has an arc-shaped structure. Multiple force-applying seats 412 form a gap ring. The gap ring expands radially through the contact between the force-applying seat 412 and the conical positioning section 310, thereby driving the anchor 410 to extend outward along the radial groove 201 and driving the cutting edge 411 to insert into the well wall, thus achieving anchoring.

[0031] In order to avoid interference between the anchor 410 and the interface section 210 after radial expansion, in this embodiment, the radial groove 201 is provided with a receiving groove 202 at the end near the interface component 200. The receiving groove 202 has the same shape as the side of the force-applying seat 412 away from the interface component 200, and is used to accommodate the force-applying seat 412 when the anchor 410 expands radially.

[0032] Regarding the structural composition of connector assembly 300, specifically: The connector assembly 300 also includes a compression anchoring section 320 and a transition section 330. Along the insertion direction of the tapered positioning section 310, the tapered positioning section 310, the transition section 330, and the compression anchoring section 320 are connected sequentially. The transition section 330 is a cylindrical tube structure with a diameter smaller than the tube body 100, used to ensure that the connector assembly 300 and the interface assembly 200 have sufficient insertion depth to achieve stable docking. The compression anchoring section 320 is tapered, used to achieve a wedge-tight docking with the interface section 210. The axial insertion of the connector assembly 300 sequentially passes through the tapered positioning section 310, the transition section 330, and the compression anchoring section 320 to complete the guiding, docking, and wedge-tightening operations.

[0033] To remove the limitation on the inner diameter of the conical positioning section 310 after the self-supporting sleeve is anchored, in this embodiment, a fracturing annular groove 301 is provided between the transition section 330 and the conical positioning section 310. When the pumped fluid injected from the ground impacts the conical positioning section 310, the fracturing annular groove 301 breaks, separating the conical positioning section 310 from the transition section 330, thereby removing the limitation on the inner diameter of the conical positioning section 310. The wall thickness of the fracturing annular groove 301 region in the radial direction of the pipe body 100 is set to 2-3 mm.

[0034] To ensure complete removal of the detached conical positioning section 310 and prevent it from remaining inside the self-supporting sleeve, in this embodiment, the inner wall of the conical positioning section 310 is provided with crack-prone grooves 302, with multiple crack-prone grooves 302 evenly distributed around the axis of the conical positioning section 310. When the pumped fluid injected from the ground impacts the conical positioning section 310, each crack-prone groove 302 breaks, causing the conical positioning section 310 to disperse into multiple fragments smaller than the pipe diameter, which can then detach from the self-supporting sleeve along with the pumped fluid.

[0035] To ensure that the easily broken ring groove 301 and the easily cracked groove 302 will break when the pump pressure fluid impacts, in this embodiment, the easily broken ring groove 301 and the easily cracked groove 302 are both provided with multiple easily broken holes.

[0036] In summary, the specific working process of the self-supporting casing string for the horizontal section of a horizontal well provided in this embodiment is as follows: A section of self-supporting casing is installed at the front end of the insertion tool and inserted into the wellbore through the tool. The connector assembly 300 is the lower end, and the interface assembly 200 is the upper end. After the first section of self-supporting casing reaches the bottom, it stops moving. The insertion tool is then separated from the current self-supporting casing and pulled out, and the next section of self-supporting casing is inserted. The connector assembly 300 of the subsequent self-supporting casing is inserted into the interface assembly 200 of the previous self-supporting casing to achieve docking. The insertion tool is then separated from the current self-supporting casing and pulled out, and the next section of self-supporting casing is inserted again, repeating this process multiple times.

[0037] The conical positioning section 310, transition section 330, and compression anchoring section 320 are sequentially inserted into the interface section 210. The conical positioning section 310 abuts against the gap ring formed by the force-applying seat 412, and through axial insertion, drives each anchor 410 to extend outward along the radial groove 201, thereby driving the cutting edge 411 to insert into the well wall. When the transition section 330 is inserted into the interface section 210, the radial extension of each anchor 410 reaches its maximum value, and the anchoring between the self-supporting casing and the well wall is completed. When the conical compression anchoring section 320 is inserted into the interface section 210, a wedge seal is formed. Multiple self-supporting casing sections are sequentially connected to form a complete casing string, and each self-supporting casing section is anchored to the well wall, that is, the entire casing string is anchored to the well wall.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A self-supporting casing string for the horizontal section of a horizontal well, characterized in that, include: Multiple self-supporting casings connected end to end, each self-supporting casing includes a casing body (100), an interface assembly (200), a joint assembly (300), and an anchoring assembly (400). The anchoring assembly (400) includes multiple anchors (410) installed in the interface assembly (200). The interface assembly (200) and the joint assembly (300) are located at both ends of the casing body (100). Two adjacent self-supporting casings are connected by inserting the joint assembly (300) into the interface assembly (200). At the same time, the joint assembly (300) abuts against and pushes each anchor (410) to cause the anchoring assembly (400) to expand radially, thereby anchoring the self-supporting casing to the well wall.

2. The self-supporting casing string for horizontal sections of horizontal wells according to claim 1, characterized in that: The interface component (200) includes an interface segment (210), which is fixedly disposed at one end of the tube body (100) and has multiple radial grooves (201) around its own axis. Each radial groove (201) has an anchor (410) sliding on it. The radial extension of the anchor (410) is used to anchor the pipe (100) to the well wall.

3. The self-supporting casing string for the horizontal section of a horizontal well according to claim 2, characterized in that: The anchoring assembly (400) also includes a stop (420), and the radial groove (201) has small holes on its sidewall; The anchor (410) has a slot (401), and the stop (420) is inserted into the small hole and snapped into the slot (401) of the anchor (410) to limit the anchor (410) and prevent the anchor (410) from extending before reaching the target position. When the self-supporting sleeve reaches the target position and the connector assembly (300) is inserted into the interface assembly (200), the stop (420) is sheared and broken, thereby releasing the anchor (410).

4. The self-supporting casing string for the horizontal section of a horizontal well according to claim 2, characterized in that: An anchor (410) has a cutting edge (411) at one end near the well wall. The connector assembly (300) is provided with a tapered positioning section (310), which is used to drive the anchor (410) to extend outward along the radial groove (201) by abutting against the anchor (410), and drive the cutting edge (411) to insert into the well wall to achieve anchoring.

5. The self-supporting casing string for the horizontal section of a horizontal well according to claim 4, characterized in that: An anchor (410) is provided with a force-applying seat (412) at the end away from the cutting edge (411), and the force-applying seat (412) is an arc-shaped structure; Multiple force-applying seats (412) form a gap ring. The gap ring expands radially through the contact between the force-applying seats (412) and the conical positioning section (310), thereby driving the anchor (410) to extend outward along the radial groove (201) and driving the cutting edge (411) to insert into the well wall to achieve anchoring.

6. The self-supporting casing string for the horizontal section of a horizontal well according to claim 5, characterized in that: The radial groove (201) near the interface assembly (200) is also provided with a receiving groove (202). The receiving groove (202) has the same shape as the side of the force seat (412) away from the interface assembly (200) and is used to accommodate the force seat (412) when the anchor (410) expands radially.

7. The self-supporting casing string for the horizontal section of a horizontal well according to claim 5, characterized in that: The joint assembly (300) also includes a compression anchoring section (320) and a transition section (330). Along the insertion direction of the conical positioning section (310), the conical positioning section (310), the transition section (330), and the compression anchoring section (320) are connected in sequence; The transition section (330) is a cylindrical tube structure with a diameter smaller than that of the tube body (100), which is used to ensure that the joint assembly (300) and the interface assembly (200) have sufficient insertion depth to achieve stable docking; The compression anchoring section (320) is set in a conical shape to achieve a wedge-tight connection with the interface section (210); The axial insertion of the joint assembly (300) is completed by guiding, docking and wedging through the tapered positioning section (310), the transition section (330) and the compression anchoring section (320).

8. The self-supporting casing string for the horizontal section of a horizontal well according to claim 7, characterized in that: A breakable annular groove (301) is provided between the transition section (330) and the conical positioning section (310); When the pumped fluid injected from the ground impacts the conical positioning section (310), the fragile ring groove (301) breaks, causing the conical positioning section (310) to separate from the transition section (330), thereby releasing the conical positioning section (310) from the limit on the diameter.

9. The self-supporting casing string for the horizontal section of a horizontal well according to claim 8, characterized in that: The inner wall of the conical positioning section (310) is also provided with crack-prone grooves (302), and multiple crack-prone grooves (302) are evenly distributed around the axis of the conical positioning section (310); When the pumped fluid injected from the ground impacts the conical positioning section (310), each crackable groove breaks and the conical positioning section (310) is dispersed into multiple fragments smaller than the pipe diameter, which can detach from the self-supporting sleeve along with the pumped fluid.

10. The self-supporting casing string for the horizontal section of a horizontal well according to claim 9, characterized in that: Both the easily broken annular groove (301) and the easily cracked groove (302) are provided with multiple easily broken holes.

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